Lamp and bell control circuit



y 5, 1970 D. A. STRATTON 3,510,671

LAMP AND BELL CONTROL CIRCUIT Filed NOV. 29, 1968 I NVEN TOR. .UDNALJJ A. 5 THAT Tm BY 9@ ATTYB.

United States Patent O US. Cl. 30739 7 Claims ABSTRACT OF THE DISCLOSURE 'minutes.

BACKGROUND OF THE INVENTION This invention relates generally to a lamp and bell control circuit, and, more particularly, to an improved circuit for ringing a bell for several seconds in response to a vehicle actuated switch and for turning a yard light on for several minutes in response to either the vehicle operated switch or a manually operated switch.

A number of different types of lamp control circuits and bell control circuits have been developed in the past. An example of one form of light control circuit is a circuit which turns on either a garage light or a yard light, or both, when a garage door is opened and turns off the light after a predetermined time delay after the garage door is closed. A number of different types of bell control circuits are also available, for example, control circuits used in burglar alarms and control circuits used for ringing bells in gas stations to notify employees that a customer has entered. A typical bell control circuit used in a gas station is merely a pneumatically operated driveway switch connected -to ring a bell.

SUMMARY OF THE INVENTION The present invention includes a control circuit for operating a yard light either alone or in combination with a bell. The yard light, once turned on, will remain on for several minutes. The bell, which is operated by a switch such as a pneumatic driveway switch or a photoelectric switch, will ring for several seconds after the switch is opened.

The yard light is turned on whenever a light control relay is energized, while the bell rings whenever a bell control relay is energized. The light control relay is initially energized either by a manually operated, normally-open push button switch or by the bell control relay. Once energized, the light control relay has a pair of holding contacts which maintain the light control relay in an energized state. The holding contacts are connected through a delay relay which opens several minutes 'after the light control relay is energized.

The bell control relay is a low voltage, direct current relay operated by a switch such as a pneumatic driveway switch or a photoelectric switch. A series resistor and capacitor are connected across the control winding of the bell control relay. The capacitor is charged when the switch is closed to energize the bell control relay. When the switch is opened, the capacitor discharges through the resistor and the control winding of the bell control relay to hold the relay closed for several seconds. Therefore, the bell will ring for several seconds even though the switch is only momentarily operated.

3,510,671 Patented May 5, 1970 It is the primary object of the invention to provide an improved control circuit for operating a yard lamp either alone or in combination with a bell.

Brief description of the drawing The single figure shows a schematic circuit diagram of a lamp and bell control circuit constructed in accordance with the invention.

Description of the preferred embodiment Referring now to the single figure, a schematic circuit diagram of the lamp and bell control circuit is shown in detail. The lamp and bell control circuit 10 has a pair of input terminals 11 and 12 which are connected to a conventional -volt, 60-hertz power source. The power line 11 is connected in series through a fuse 13 and the primary winding of a low voltage transformer 14 to the power line 12. The low voltage transformer 14 may, for example, be a filament transformer having a 12.6- volt center tapped secondary winding. The center tap 15 for the secondary winding is connected to a common ground terminal. One end 16 of the secondary winding is connected through a control winding 17 for a light control relay 18, through a nonmally-open push button switch 19 to the grounded center tap 15. The push button switch 19 may, for example, be a conventional low voltage doorbell switch.

The light control relay- 18 includes a pair of normallyopen switch contacts 20 and a pair of normally-open switch contacts 21. The power line 11 is connected through a fuse 22 to one of the switch contacts 20, while the other of the switch contacts 20 is connected through a line 23 and a high voltage yard light 24 to the other power line 12. Thus, when the light control relay 18 is actuated, the switch contacts 20 close to apply 110 volts to the yard light 24. A resistor 25 and a capacitor 26 are connected in series across the switch contacts 20 to reduce arcing across the contacts 20 when the relay 18 is de-energized.

The switch contacts 21 in the light relay 18 function as a holding switch connected in parallel with the switch 19. A delay relay 27 is connected in series between one of the switch contacts 21 and the grounded center tap 15 of the transformer 14. The delay relay 27 may include a bimetallic switching element 28 and a heater resistance 29, or may be electronically operated. The heater resistance 29 is connected in parallel with the yard light 24 for energization when the switch contacts 20 are closed. Therefore, it can be seen that the control winding 17 of the light control relay 18 is energized when the switch 19 is pushed, closing the pairs of switch contacts 20 and 21. When the switch contacts 20 are closed, the yard light 24 is turned on and the heater 29 in the delay relay 27 starts heating the bimetallic switch element 28. The switch contacts 21 hold the relay 18 in the energized state until the bimetallic switching element 28 in the delay relay 27 opens.

A full wave rectifier, including a pair of diodes 30 and 31, connects the end 16 and the other end 32 of the secondary winding of the transformer 14 to one side of a control coil 33 for a bell control relay 34. The bell control relay 34 is a direct current relay having a pair of normally-open bell switch contacts 35 and a pair of normally-open lamp switch contacts 36. The other end of the control winding 33 is connected through a normally-open signal switch 37 to the grounded center tap 15 of the seocndary winding of the transformer 14. The signal switch 37 may, for example, be a photoelectric switch, a pneumatic driveway switch, or any other signal operated switch. When the signal switch 37 closes, the control coil 33 of the relay 34 is energized to close the pair of switch contacts 35 and 36. A timing network, including a series resistor 38 and capacitor 39, is connected in parallel with the control coil 33 for the relay 34. The capacitor 39 is charged when the control coil 33 is energized by closing the switch 37, the charging rate being limited mainly by the resistor 38. When the signal switch 37 is opened, the capacitor 39 discharges through the resistor 38 and the control coil 33 to hold the pairs of switch contacts 35 and 36 closed for several seconds after the signal switch 37 is opened.

A conventional bell 40 is connected in series with the bell switch contacts 35 in the relay 34 and the ends 16 and 32 of the secondary winding of the transformer 14. The bell 40 will ring whenever the control winding 33 of the relay 34 is energized to close the switch contacts 35. The light control switch contacts 36 in the relay 34 are connected in parallel with the push button switch 19 to energize the control winding 17 of the light control relay 18 whenever the bell control relay 34 is energized by closing the signal switch 37.

In operation, assume, for example, that the signal switch 37 is a pneumatic driveway switch. When a vehicle crosses the pneumatic driveway switch, the bell control relay will be energized to ring the bell 40 for several seconds and to energize the light control relay 18 to turn on the yard light 24 for several minutes. The push button switch 19 is used to turn on the yard light 24 for several minutes without ringing the bell 40. The low voltage transformer 14 isolates the push button switch 19, the signal switch 37 and the bell 40 from the high voltage power lines 11 and 12, thereby greatly reducing the hazard of electrical shock.

It will be appreciated by those skiled in the art that various modifications may be made in the circuit without departing from the scope of the claimed invention.

What I claim is:

1. An improved control circuit for operating a lamp and a bell, comprising, in combination, a lamp control relay, means for energizing said lamp relay, timing means responsive to the energization of said lamp relay for maintaining said lamp relay energized for a predetermined period of time, means for energizing the lamp when said lamp relay is energized, a bell control relay, switch means for energizing said bell relay, timing means responsive to the energization of said bell relay for maintaining said bell relay energized for a period of time shorter than said predetermined period of time in which said lamp relay remains energized, and means for energizing said lamp relay and said bell when said bell relay is energized.

2. An improved control circuit for operating a lamp and a bell as defined in claim 1, wherein said timing means responsive to the energization of said lamp relay for maintaining said lamp relay energized for a predetermined period of time includes a delay relay having a bimetallic switching element.

3. An improved control circuit for operating a lamp and a bell as defined in claim 1, wherein said timing means responsive to the energization of said bell relay for maintaining said bell relay energized for a period of time shorter than said predetermined period of time includes an R-C timing network.

4. An improved control circuit for operating a lamp and a bell as defined in claim 1, wherein said switch means for energizing said bell relay is a photoelectric switch.

5. An improved control circuit for operating a lamp and a bell as defined in claim 1, wherein said switch means for energizing said bell relay is a pneumatically actuated driveway switch.

6. An improved control circuit for operating a lamp and a bell as defined in claim 1, wherein said means for energizing said lamp relay is a normally-open, manually operated switch.

7. An improved control circuit for operating a lamp and a bell, comprising, in combination, a lamp control relay, means including a normally-open switch for energizing said lamp relay, timing means responsive to the energization of said lamp relay for maintaining said lamp relay energized for a predetermined period of time, said timing means including a delay relay, means for energizing the lamp when said lamp relay is energized, a bell control relay, means including a switch for energizing said bell relay, timing means including an R-C network responsive to the energization of said bell relay for maintaining said bell relay energized for a period of time shorter than said predetermined period of time in which said lamp relay is energized, and means for energizing said lamp relay and the bell when said bell relay is energized.

References Cited UNITED STATES PATENTS 2,435,370 2/1948 Speer 317-141 X 2,912,685 11/1959 Thomas 317-141 X 3,017,623 1/ 1962 Bishofberger 315360 X 3,185,782 5/1965 Lakin 317141 X ROBERT K. SCHAEFER, Primary Examiner T. B. JOIKE, Assistant Examiner U.S. c1. X.R. 

